The operators of Hamilton Island’s luxury retreats and leisure facilities have agreed to backpay thousands of staff more than $28 million after admitting to underpaying them minimum rates for almost a decade.

The Fair Work Ombudsman found Hamilton Island Enterprises Ltd – which is owned by the billionaire Oatley family and operates the island’s accommodation as well as the marina, airport, retail stores, restaurants and leisure facilities – underpaid full-time hospitality staff through salaries that were not enough to cover overtime, shift work and weekend penalty rates.